Congress last year passed a bill to reduce the interest rate on federally backed student loans to 3.86 percent, down nearly 3 points from the previous year. But that change was only for new loans. Students and graduates who already had borrowed are still stuck with some of the highest rates ever.

That means many students are paying substantially more — sometimes as much as 7 percent interest — for loans issued before this year. Unlike homeowners and businesses, students cannot refinance their federal student loan debt.

Bellows was at Bowdoin College pushing the bill introduced Tuesday by Sen. Elizabeth Warren, D-Massachusetts, that would allow all student debt holders to refinance their federally backed loans — and even some private loans — down to the new rates, saving them hundreds or even thousands of dollars per year. The bill would be paid for by instituting a minimum tax rate of 30 percent on income over $1 million.

“I don’t think the government should be loaning money to students at a higher interest rate than they loan money to the biggest banks in the country,” Bellows said.

Bellows graduated from a private college in 1997 with about $30,000 in debt. She entered an economy with an unemployment rate of about 3 percent, she said, so back then, it was easy to find work. Since then, a lot has changed.

“Today, unemployment for young people, the class of 2013, is over 10 percent. Young people are confronting an economy where it’s difficult to find work and are finding it difficult to make those payments,” she said.

About 40 million Americans are carrying student debt, with the average burden on bachelor’s degree graduates at about $29,400. National student debt, worth about $1.2 trillion, surpasses that of credit cards and auto loans. It’s second in value only to mortgage debt. The U.S. Government Accountability Office estimated in January that the federal government will make $66 billion this year on student loans disbursed between 2007 and 2013.

UMaine Augusta senior and Michigan native Cali Davis is a biology student. She said her father had a stroke last year, and her mother is unemployed. Neither can afford to help her pay for college, so she’s racked up more than $45,000 in student loans. She wants to attend pharmacy school but is concerned about taking on additional debt.

Looking out at the job market, she’s discouraged at how difficult it is to find a job in her field — despite renewed emphasis on science degrees. Because she had to work through college, Davis was unable to take an internship, and so she has no experience in the field.

“Taking all this debt just isn’t paying off when it comes to finding work — even if it’s just enough to pay it off,” she said. “Congress needs to pass this bill, for those of us who did what we were advised to do.”

While Bellows was in Brunswick, Collins was focused on Boko Haram, the Islamic militant group in Nigeria that has kidnapped hundreds of schoolgirls and threatened to sell them into slavery or forced marriage. She and U.S. Sen. Barbara Boxer, D-California, on Thursday introduced a bill to make preventing violence against girls and women a top diplomatic priority for the United States.

Her communications director, Kevin Kelley, said Collins would examine Warren’s bill, and he noted it had not yet been reviewed by the Senate Finance Committee.